The tire/wheel assembly capable of being equipped with an air pressure detecting unit for detecting the air pressure of a tire is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2002-283801. In this tire/wheel assembly, the unbalance amount and unbalance range (region within which an unbalance occurs) of the tire/wheel assembly vary depending on whether an air pressure detecting unit is mounted thereon.
In the tire/wheel assembly set forth in the Japanese Unexamined Patent Application Publication No. 2002-283801, counterbalance weight equivalent to the weight of the air pressure detecting unit is provided to a rim section or disc section of the wheel so that the counterbalance weight and the air pressure detecting unit are positioned substantially symmetrically about the rotation center of the wheel (i.e., the rotation center of the tire/wheel assembly), thereby performing a setting such that a target barycentric position (barycentric position in design) of the wheel substantially conforms to the rotation center of the wheel. As a result, in this tire/wheel assembly, the mounting of the air pressure detecting unit onto the wheel, substantially cancels the weight unbalance with respect to the rotation center of the wheel.
However, in the above-described tire/wheel assembly, if the wheel is not equipped with the air pressure detecting unit, there occurs a weight unbalance equivalent to the weight of the air pressure detecting unit because of the counter balance weight provided to the rim section or the disc section of the wheel. As a consequence, the maximum value of a balance weight to be used when making a rotational balance adjustment of the wheel becomes higher than the case where the air pressure detecting unit is mounted on the wheel, by the weight of the air pressure detecting unit. This may make it impossible to properly make a rotational balance adjustment using a small amount of balance weight.
Such a problem can be solved by providing no counter balance weight equivalent to the weight of the air pressure detecting unit, to the rim section or the disc section in a wheel adopted in a tire/wheel assembly without the air pressure detecting unit. However, in this case, besides a wheel for a tire/wheel assembly with the air pressure detecting unit (i.e., a wheel having thereon a counter balance weight equivalent to the weight of the air pressure detecting unit), it is necessary to prepare for a wheel for a tire/wheel assembly without the air pressure detecting unit (i.e., a wheel having thereon no counter balance weight equivalent to the weight of the air pressure detecting unit). This necessitates the manufacturing and managing of two kinds of wheels, thereby causing new problems such as an increase in costs and the like.